package demo1;

public class Computer
{
    public void powerOn(){
        System.out.println("打开笔记本电脑");
    }
    public void powerOff(){
        System.out.println("关闭笔记本电脑");
    }
    public void usbDevice(USB usb)
    {
        usb.openDevice();
        if(usb instanceof Mouse)
        {
            Mouse mouse=(Mouse) usb;//向下转型
            mouse.click();
        }
        else if(usb instanceof KeyBoard)
        {
            KeyBoard keyBoard=(KeyBoard) usb;
            keyBoard.inPut();
        }
        usb.closeDevice();
    }
}
